Ortho Baltic, a Lithuanian manufacturer of bespoke 3D printed medical implants, recently made the decision to adopt a CT inspection technology to improve the quality of its products. To do so, Ortho Baltic reached out to Nikon Metrology, an expert in industrial measurement, inspection, and quality assurance.

The Kaunas-based company is the first in the Baltic region to offer patient-specific temporomandibular joint (TMJ) endoprostheses, which are implanted to help patients recover the functionality of a joint. More generally, the company has been working towards establishing patient-specific implants as the norm, as well as making them more accessible in terms of cost.

Ortho Baltic has been using 3D printing technologies in its operations since 2012, as has seen the benefits of using AM to create made-to-order bespoke implants based on a patient’s CT scan. Currently, the company produces patient-specific joints, cranial implants, spinal implants, bone plating systems, dental and jaw restoration implants, and surgical guides.

In order to certify that these one-off implants and guides are up to par, the medical device manufacturer has come to rely on “one-off inspections” which are made possible with Nikon Metrology’s systems.

A 3D printed acetabular implant being scanned and inspected

To meet its stringent demands, Ortho Baltic chose to leverage Nikon Metrology’s XT H 225 system, which includes a Varian 4030 digital panel and Inspect-X software. The inspection system can reportedly accommodate large parts (weighing up to 15 kg) and is capable of penetrating dense materials (like titanium alloys) with its 225 kV micro-focus source.

For producing its patient-specific medical devices, Ortho Baltic uses a variety of 3D printing processes and materials. For instance, to manufacture implants it typically uses a direct laser metal sintering (DMLS) process and a medical grade-5 titanium alloy (Ti6Al4V). For making surgical guides and implant models, the company uses selective laser sintering (SLS) and PA 2200, a biocompatible polymer.

“To create the patient-specific anatomical models, 3D reconstruction engineers work with a radiologist (if necessary) using the patient’s radiological data to perform a 3D reconstruction. The anatomical bone structures are segmented and virtual 3D models are prepared,” explained Milda Jokymaitytė, a clinical engineer at Ortho Baltic.

A patient-specific 3D printed temporomandibular joint (TMJ)

Jokymaitytė goes on to say that the entire process of manufacturing a custom implant (specifically a TMJ prosthesis), from printing, quality control, packaging, and sterilization, took about four weeks. “From this point onwards, the pre-surgical planning commences between patient and surgeon, ultimately leading to surgery completion.”

To check the quality of its 3D printed parts, Ortho Baltic uses a multi-sensor coordinate measuring machine (CMM) in combination with a micro-CT system, provided by Nikon Metrology. Micro-CT scanning has offered the company a non-destructive and non-invasive way to check and qualify the interior of a 3D printed part.

“For today, micro-CT is the best solution for our product development and quality control,” said Domantas Ozerenskis, Product Quality Manager at Ortho Baltic. “3D printing is a very complicated technology and has a big variation of processing parameters, consequently it is hard to predict the structure quality and geometry of a printed part.”

Ultimately, Ortho Baltic has stated that Nikon Metrology’s quality assurance system has proven to be an “irreplaceable” tool in its patient-specific 3D printed implant manufacturing. “The Nikon solution offers better knowledge of what we are manufacturing; it gives better precision and understanding of 3D printing errors and deviations,” commented Ozerenskis.